Leak free semi-stackable drain pan

ABSTRACT

The present invention relates to drain pans and the process of making the same, and more particularly to a leak proof drain pan that is semi-stackable during storage and can be manufactured from a single piece of steel without the use of a press, die or tooling. The drain pan includes corner sections created from a unique folding system which eliminates seams and thus the need for any sealing of the seams.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to drain pans, and more particularly to aleak proof drain pan that is semi-stackable during storage and can bemanufactured from a single piece of steel without the use of a press,die, welding or tooling.

2. Description of the Prior Art

Various types of drain pans are known in the art and can be used in anynumber of situations for collecting various types of fluids such as oilor water. Such drain pans should be leak free, but require sealants toeffectively seal the seams of the drain pan. Drain pans exist in theautomotive and trucking industries, and can be used for heavy duty truckand trailer tubeless dual wheels, allowing the user to cleanly andsafely drain oil or grease from the axles. Drain pans can also be usedin the food industry, where drain pans are placed underneath fryingmachines to catch cooking oil and grease dripping or to completely drainthe cooking oil. Drain pans can be used for water heaters to catchexcess water. A household dishwasher can include a drain pan designed torelocate leaking fluids to an observable location. Other types ofappliances that can use drain pans include refrigerators and washingmachines for catching excess water leaking from the appliance. Drainpans can be used to catch excess grease from underneath barbecue grillsand inside home grills.

A cooling coil used in air conditioning apparatus such as furnaces, airhandling units, and heat pumps extracts moisture from the air which isbeing flowed externally across the coil (by a blower portion of theapparatus) and cooled by the coil for delivery to a conditioned spaceserved by the apparatus. Air flowing across the coil is dehumidified asit is cooled, causing condensation to form on the coil. Thiscondensation must be disposed of to prevent freezing of the coil anddamage to the surrounding building structure. Typically, a drain pan islocated beneath the coil to receive condensate runoff. The pan includesan opening in a bottom part of the pan to conduct the condensateaccumulated in the pan to an external drainage conduit.

It is advantageous to reduce water retention in the pan to the extentfeasible, not only to reduce the likelihood of condensate spillage fromthe pan onto the adjacent building structure, but also to inhibit theformation of mold, rust and other undesirable byproducts of stagnantwater in the pan which may lead to reduction in the quality of airdelivered to the conditioned space. Further, air flowing across the heatexchanger cooling coil may pick up moisture from excessive wateraccumulation in the pan, which may result in unwanted humidity in theair supplied to an indoor space.

Drain pans of various types are known in the art. These prior art drainpans are typically rectangular in shape and cannot fit inside oneanother when stacked for storage. Because of limited availability ofshelf space in retail establishments, it is desired to stack the drainpans as closely together as possible. FIG. 10 of the present applicationshows a typical set of stacked drain pans according to the prior art. Ascan be seen, the drain pans of the prior art are stacked one on top ofanother and are not nested together. Thus, stacking multiple drain pansfor storage, shipping, etc. will take up more space.

U.S. Pat. Nos. 4,632,268 and 4,513,865 disclose stackable oil drainpans. As can be seen from FIGS. 4 and 5 of both references, the drainpan has a male protrusion on top of the pan and a corresponding femaleindentation on the bottom. When stacked on top of each other, the drainpans do stack more easily. However, the amount of excess space savedfrom stacking is relatively small. As can be seen from the FIGS. 4 and5, the main body of the drain pans do not fit inside one another.

Some of the prior art drain pans are nestable when stacked. A typicaldrain pan of this nature is shown in U.S. Pat. No. 6,718,788. However,this drain pan has a big disadvantage based on the manufacture of thedrain pan itself. The drain pan is fabricated by use of a press, die andtooling. The drain pan is pressed into a die and the corners are crimpedto form the usual rectangular shape with crimped corners. The type ofpress used is a large hydro-formed press which includes tooling tomanufacture only one size at a time. Each different size drain panrequires a different die with separate tooling. Since the die andtooling must be custom made to accommodate each drain pan size, themanufacturing costs are high. Thus, manufacture of this type of drainpan is very expensive and is not easily adaptable for fabricatingdifferent size drain pans unless large numbers of each size of pan aremade.

Furthermore, during the foregoing manufacturing process using the press,the large force exerted by the press to form the drain pan can cause thesteel to crack at the corners. If these cracks are not found at the timeof manufacture, this can create possible leakage of the condensate whenthe drain pan is in use. Hair-line cracks in steel are often not visibleto the naked eye. Therefore, the prior art drain pans have some majordisadvantages.

Some of the prior art nestable pans, such as the drain pan disclosed inU.S. Pat. No. 6,718,788, can become jammed when stacked, making removalof the pans tedious and slow. If there is tight stacking, it might notbe possible to separate the drain pans.

It would be advantageous to reduce the amount of space the drain pansoccupy when stacked upon one another for storage or shipping purposes.In this regard, it would be useful for a drain pan to fit inside anotherdrain pan.

Furthermore, it would be an advantage to significantly reduce the costsand time associated with the manufacture of drain pans by eliminatingthe need for a die and tooling to be used with a press. The eliminationof the press during the manufacturing process would also reduce thelikelihood of cracks or flaws in the drain pan.

As can readily be seen from the foregoing, a need exists for a drain panstructure which eliminates or at least substantially reduces theabove-mentioned problems, limitations and disadvantages ofconventionally constructed drain pans. It is to this need that thepresent invention is directed.

SUMMARY OF THE INVENTION

As described in the Description of the Prior Art, drain pans are knownin the art and can be used in any number of situations for collectingvarious types of fluids such as oil or water in the form ofcondensation. Such drain pans should be leak free, but require sealantsto effectively seal the seams of the drain pan.

An object of the present invention is to provide a drain pan which isleak proof and can be manufactured without the need of a press, die andtooling.

Another object of the present invention is to provide a drain pan whichcan be manufactured easily at relatively low cost and is easilyadaptable for being manufactured in various sizes.

Yet another object of the present invention is to provide a drain panthat can be manufactured from one piece of steel or other appropriatemetal, wherein the single piece of steel or other metal is folded uponitself to form the drain pan, without the formation of hairline or othertypes of cracks.

A further object of the present invention is to provide a drain panwhich is semi-stackable for reducing the space on the shelves ofwholesalers and other storers of such pans.

Another object of the present invention is to provide a drain pan whichdoes not require the use of sealants to prevent leaks.

Still yet another object of the present invention is to provide a drainpan with a drain plug that can be located on any side of the drain panfor preventing overflow of the pan.

The foregoing objects are achieved according to the preferred embodimentof the invention by the provision of a drain pan from a single piece ofsheet metal which is uniquely folded to create a seamless drain pan. Thedrain pan includes folded corner sections which are folded toward theinner portion of the drain pan as described below, which enables thestacking of the drain pans in a stable manner, with easy placement ofdrain pans in the stack and fast removal therefrom, without anypossibility of jamming.

BRIEF DESCRIPTION OF THE DRAWINGS

Other characteristics and advantages of the present invention willemerge from reading the detailed description hereinbelow of nonlimitingembodiments of the invention, and examining the attached drawingswherein:

FIG. 1 is a perspective view of the leak free semi-stackable drain pan.

FIG. 2 is a section view of the drain pan of FIG. 1 taken along the line2-2.

FIG. 3 is a section view of the drain pan of FIG. 1 taken along the line3-3.

FIG. 4 is an enlarged perspective view of an unfolded corner of thedrain pan of FIG. 1 showing dotted lines where the drain pan will befolded.

FIG. 5 is an enlarged perspective view of a partially folded corner ofthe drain pan of FIG. 1 showing the direction of the folds indicated byarrows.

FIG. 6 is an enlarged perspective view of a corner of the drain pan ofFIG. 1 showing the direction of the final fold of indicated by arrows.

FIG. 7 is an enlarged perspective view of a corner of the drain pan ofFIG. 1 showing a completely folded corner with completely folded topedges.

FIG. 8 is a top view of the drain pan of FIG. 1 as a single sheet ofmetal completely unfolded, prior to its fabrication into a drain pan.

FIG. 9 is a front view of multiple drain pans of FIG. 1 placed upon oneanother in a semi-stackable fashion.

FIG. 10 is a front view of multiple drain pans according to the priorart in a stacked configuration.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

As discussed throughout the specification, the term “crimp” or “crimped”means corrugated or to produce a corrugated surface. The term“semi-stackable” means that one drain pan is inserted with its open topfacing upwards, into a lower drain pan with its open top facing upwards,with the upper edge of the inserted end wall contacting the inside ofthe corresponding end wall of the drain pan into which the inserteddrain pan is being placed, and the lower edge portion of the oppositeend wall of the inserted drain pan resting on the upper edge of the endwall of the lower drain pan so that the drain pan at the top of thestack can be easily grasped to enable lifting of the pan from the stack.The inclination of the next drain pan in the stack is reversed to limitthe tilting of the stack. An example of stacking of the semi-stackabledrain pan is shown in FIG. 9.

Disclosed according to the present invention is a drain pan and a methodof producing the drain pan. As will be more fully explained hereinafter,the drain pan of the present invention is preferably folded from asingle sheet of steel or similar material without the use of a press andthe necessary die and tooling associated with the press. The drain panis semi-stackable for reducing the space on the shelves of wholesalers,and making removal of one or more drain pans easy whether done manuallyor with an appropriate tool or appropriate equipment.

FIG. 1 shows a perspective view of the leak free semi-stackable drainpan generally designated at 10. Drain pan 10 is seamless and does notleak. As shown, drain pan 10 is substantially square shaped and includesa bottom wall 12 which can have a width of about 24 inches width and alength of 24 inches. However, drain pan 10 is not limited by thesedimensions or being substantially square shaped and could retain othershapes such as a rectangle, for example, depending upon the applicationof the drain pan and the different sizes of the air conditioner. Drainpan 10 could also be curved or have irregular shapes as well. Drain pan10 also includes a front wall 14, a rear wall 16 and two side walls 18.Front wall 14 and rear wall 16 are substantially parallel to each otherand substantially perpendicular to bottom wall 12. Side walls 18 arealso substantially parallel to each other and substantiallyperpendicular to bottom wall 12. Front wall 14 and rear wall 16 aresubstantially perpendicular to sidewalls 18. As seen in FIG. 1, sidewalls 18 also include corner sections 20 on the inside of drain pan 10resulting from the folding of the corners of drain pan 10 as discussedlater. Top edge portions 22A, 22B and 22C are located on the inside offront wall 14, rear wall 16 and side walls 18 respectively, and aremodified as described below, to serve to protect a user handling drainpan 10 from any sharp edges of the sheet metal. Top edge portion 22Coverlaps corner sections 20 of each sidewall 18 as shown in FIG. 1. Adrain fitting 24 is located on the outside of front wall 14 to drain thewater or condensation retained by drain pan 10. In use, drain fitting 24is hermetically sealed in drain pan 10 and thus does not have any leaks.When installed in an air conditioner, freezer or refrigeration unit, forexample, a hose is attached to drain fitting 24 in the manner shown inU.S. Pat. No. 6,718,788 for draining condensates from drain pan 10.Drain fitting 24 can advantageously include as an integral unit, acylindrical tube or male adaptor 25A extending from a nut portion 25Bfrom which extends an externally threaded tubular portion extendingthrough wall 14 (or some other wall). Male adaptor 25A is held in placeby internal nut or fastener 26 screwed to abut the inside surface ofwall 14, and a gasket 27 is located between nut portion 25B and theexternal surface of wall 14.

Drain pan 10 is formed by folding of a blank 40 as shown by thefictitious fold lines shown in FIG. 8. Drain pan 10 is not crimped,meaning it does not have corrugated surfaces. Preferably the blank ismade from steel and usually is made of sheet metal. An appropriatethickness is 0.0193 inches. However, other materials that create arigid, leak proof drain pan when folded can also be used. The sheetmetal is cut to the desired blank size. The dotted lines shown in FIG. 8display where blank 40 is folded to create drain pan 10 in FIG. 1. Eachsection separated by the dotted lines substantially corresponds to theparts of drain pan 10 as described above. Bottom wall 12 issubstantially square-shaped although it is not limited to thisembodiment as mentioned above. Blank 40 also includes front wall 14,rear wall 16 and side walls 18. A drain plug hole 30 is punched out offront wall 14 to accommodate drain plug 24. Drain plug hole 30 can bealso located in rear wall 16 or side walls 18. Of course, more than onedrain plug hole 30 can be punched to accommodate multiple drain plugs24. Top edges 22 are also part of blank 40 and are located on each frontwall 14, rear wall 16 and side walls 18 respectively. Top edge portions22A, 22B and 22C are slightly chamfered at each end to allow forclearance when folded over at each corner section 20. Of course it ispossible that top edge portions 22A, 22B and 22C are not chamfered atall or may be rounded. Top edge portions 22A, 22B and 22C do not have tobe included in drain pan 10, but they are rendered smooth as discussedbelow to prevent them from cutting a person or items during handling anduse, and to prevent them from scratching other drain pans duringstacking.

Corner sections 20 are further defined as seen in FIGS. 4 and 5. Cornersection 20 includes an outside corner 28 and an inside corner 29. FIG. 4shows a magnified corner section 20 in more detail. Corner section 20has four sides as defined by lines A and B, and phantom lines C and D.As seen in FIG. 4, a phantom line H diagonally bisects corner section 20from outside corner 28 to inside corner 29 creating a top corner section28A and bottom internal corner section 29A which are substantially thesame size. An angle a is the angle between line B and phantom line D. αis also the angle between line A and phantom line C. As shown in FIG. 4,a is about 95 degrees. However, α is not limited to being 95 degrees andcan either be an acute, obtuse or a right angle. As shown in FIG. 8, theedges between front wall 14 and rear wall 16, and bottom wall 12 areshown by phantom lines E and F, respectively. The edges between sidewalls 18 and bottom wall 12 are shown by phantom lines G.

FIGS. 5, 6 and 7 show the folding of corner section 20 as well as frontwall 14, side wall 18 and top edge portions 22A, 22B and 22C. First,considering drain pan 10 in an unfolded condition and initially in aground engaging position as shown in FIG. 8, the portion of sheet metalincluding phantom line H is forced upward from bottom wall 12 by hand orsuitable machine, rotating top corner section 28A about bottom internalcorner section 29A. Outside corner 28 is thus moved upwardly and inwardas shown by arrow X towards bottom wall 12. At the same time, side wall18 and front wall 14 are forced to fold inwardly as shown by arrows Yand Z respectively, about edges. Since top edges 22C and 22A areattached to side walls 18 and front wall 14, respectively, they too arepulled inward. However, top edges 22 are not yet folded over. When sidewalls 18 and front wall 14 become substantially perpendicular to bottomwall 12, top corner section 28A and bottom internal corner section 29Ashould be substantially coplanar. That is, lines A and B should becollinear and lines C and D should be collinear. Next, corner section 20is folded either towards side wall 18 or front wall 14. In FIG. 6,corner section 20 is folded towards side wall 18 until it issubstantially coplanar with side wall 18.

Next, top edge 22A of front wall 14 is folded inward at 180 degreesalong phantom line I as seen in FIG. 6. FIGS. 4 and 5 show phantom lineI before folding. The folding over of top edge 22A is for safety andprevents any sharp surfaces of blank 40 from cutting or injuring a userwhen handling drain pan 10. This same folding procedure is repeated forthe other three corner sections 20. Finally, each top edge 22C of eachside wall 18, as shown in FIG. 6, is folded inward at 180 degrees alongdotted line L. Arrow J shows part of top edge 22 folding over part ofcorner section 20 to the position shown in FIG. 7. Arrow K shows theremaining part of top edge 22C folding over part of side wall 18. It isimportant that these top edges 20C are folded last, since they helpsecure corner sections 20 and prevent them from unfolding at each cornerof drain pan 10. After the folding is complete, drain fitting 24 isinserted into drain hole 30 and is hermetically sealed by means of nut25B and gasket 27 as explained earlier. Drain pan 10, which was createdfrom blank 40, is now seamless and leak proof. No sealing around thecorners or any part of drain pan 10 is necessary. Furthermore, no press,die or tooling was needed to create drain pan 10. Thus, drain pan 10 isrelatively inexpensive to manufacture and creates significant costsavings compared to the previous drain pans created from a press.

After multiple drain pans 10 of the same size have been manufactured,they can be stacked as seen in FIG. 9 for storage purposes in thesemi-stackable arrangement to reduce the space on the shelves ofwholesalers or for shipment. The stacking configuration shown in FIG. 9allow for twice the number of drain pans 10 to be stacked compared tothe prior art drain pans as seen stacked in FIG. 10.

Having described the invention, it will be apparent to those skilled inthe art that alterations and modifications may be made without departingfrom the spirit and scope of the invention limited only by the appendedclaims.

1. A seamless drain pan for collecting and storing a liquid such ascondensate and the like, said drain pan comprising: a bottom wall; afront wall having a top edge portion, said front wall being integralwith and substantially perpendicular to said bottom wall; a rear wallhaving a top edge portion, said rear wall being integral with andsubstantially perpendicular to said bottom wall; a first side wallhaving a top edge portion, said first side wall being integral with andsubstantially perpendicular to said bottom wall, said first side wallbeing connected to said front wall at a first leak proof frontintersection and said first side wall being connected to said rear wallat a first leak proof rear intersection; a second side wall having a topedge portion, said second side wall being integral with andsubstantially perpendicular to said bottom wall, said second side wallbeing connected to said front wall at a second leak proof frontintersection and said first side wall being connected to said rear wallat a second leak proof rear intersection; said front wall, said rearwall, said first side wall and said second sidewall having a crosssection in the shape of a rectangle; and a corner section disposed ateach of said leak proof front intersections and each of said leak proofrear intersections, each corner section having an outside corner and aninside corner, said outside corner and said inside corner being disposedwherein a fictitious bisecting line connecting said outside corner andsaid inside corner bisects each of said corner sections, wherein eachcorner section further comprises: a top corner section integral with oneof said first side wall and said second side wall; a bottom cornersection integral with one of said front wall and said rear wall; saidtop corner section and said bottom corner section intersecting at saidfictitious bisecting line of each said corner section; wherein eachcorner section comprises said top corner section and said bottom cornersection folded one over the other along said fictitious bisecting line,said top corner section and said bottom corner section beingsubstantially coplanar and lying parallel to a selected one of saidfirst side wall, said second side wall, said front wall and said rearwall.
 2. A seamless drain pan for collecting and storing a liquid suchas condensate and the like, said drain pan comprising: a bottom wall; afront wall having a top edge portion, said front wall being integralwith and substantially perpendicular to said bottom wall; a rear wallhaving a top edge portion, said rear wall being integral with andsubstantially perpendicular to said bottom wall; at least one side wallhaving a top edge portion, said at least one side wall being integralwith and substantially perpendicular to said bottom wall, said at leastone side wall being connected to one of said front wall and said rearwall at a leak proof intersection; and a corner section disposed at saidleak proof intersection, said corner section having an outside cornerand an inside corner, said outside corner and said inside corner beingdisposed wherein a fictitious bisecting line connecting said outsidecorner and said inside corner bisects said corner section, wherein saidcorner section further comprises: a top corner section integral withsaid at least one side wall; a bottom corner section integral with oneof said front wall and said rear wall; said top corner section and saidbottom corner section intersecting at said fictitious bisecting line ofsaid corner section; wherein said corner section comprises said topcorner section and said bottom corner section folded one over the otheralong said fictitious bisecting line, said top corner section and saidbottom corner section being substantially coplanar and lying parallel toa selected one of said at least one side wall or one of said front walland said rear wall.
 3. A seamless drain pan according to claim 2,wherein said respective top edge portions of said walls are folded overthe respective corner sections to prevent unfolding of the respectivecorner sections.
 4. A seamless drain pan according to claim 2, whereinsaid drain pan has a cross section extending through said front wall,said rear wall and said at least one side wall, said cross section beingin the shape of a rectangle.
 5. A seamless drain pan according to claim2, wherein said drain pan is manufactured from sheet metal.
 6. Aseamless drain pan according to claim 5, wherein said sheet metal has athickness of approximately 0.0193 inches.
 7. A seamless drain panaccording to claim 2, further comprising a drain fitting located on theoutside of at least one of said front wall, rear wall or at least oneside wall to drain liquid from said drain pan.
 8. A seamless drain panaccording to claim 7, each of said walls having an inside surface and anoutside surface, said drain fitting comprising: a nut portion having anexternally threaded tubular portion extending through one of said walls;a male adaptor extending from said nut portion; a gasket located betweensaid nut portion and the external surface of said one of said walls; anda fastener screwed on said nut portion for abutting the inside surfaceof said one of said walls.
 9. A seamless drain pan for collecting andstoring a liquid such as condensate and the like, said drain pancomprising: a bottom wall; a front wall having a top edge portion, saidfront wall being operatively connected to said bottom wall at a leakproof front intersection; at least one side wall having a top edgeportion, said at least one side wall being operatively connected to saidbottom wall at at least one leak proof side intersection, said at leastone side wall being connected to said front wall at a respectivejuncture of said leak proof front intersection and said at least oneleak proof side intersection; and at least one corner section disposedat said respective juncture, each corner section having an outsidecorner and an inside corner, said outside corner and said inside cornerbeing disposed wherein a fictitious bisecting line connecting saidoutside corner and said inside corner, bisects said respective cornersections, said at least one corner section further including: a topcorner section operatively connected to said at least one side wall; abottom corner section operatively connected to said front wall; and saidtop corner section and said bottom corner section intersecting at saidfictitious bisecting line of said at least one corner section; whereinsaid at least one corner section comprises said top corner section andsaid bottom corner section at least partially folded one over the otheralong said fictitious bisecting line.
 10. A process of making a seamlessdrain pan for collecting liquid, the drain pan having a front wall, arear wall, opposing side walls connecting the front wall and the rearwall, and a bottom wall connected to a corresponding edge of each ofsaid walls, said process comprising the following steps: cutting a metalsheet in a generally flat rectangular form, with each side having a topedge portion extending from the respective side and being shorter thanthe respective side, each top edge portion having opposing endstransverse to the respective side and intersecting the respective sideat a juncture, and adjacent sides forming outside corners, fictitiousfirst and second lines extending from the respective junctures of theadjacent edges to an inside corner point to form a first angle, with afictitious third line extending from the respective outside corners ofthe rectangular sheet to the respective inside corner points to bisectthe first angle; folding the respective outside corners using therespective inside corner point as the respective pivots, and furthercommencing the folding of the respective opposing side walls, the frontwall and the rear wall about lines extending between adjacent insidecorner points, until the respective side walls, front wall and rear wallare generally perpendicular to the unfolded part of the metal sheet, theunfolded part being the bottom wall, the respective halves of therespective outside corners being doubled over to form a doubled overcorner section with the first and second fictitious lines being adjacenteach other with the confines of the adjacent side wall and the adjacentfront or rear wall; and folding the respective doubled over cornersections against the adjacent side wall or adjacent front or rear wall.11. The process of making a seamless drain pan according to claim 10,and further including the step of folding the respective top edgeportions so that they are adjacent to the respective side walls, frontwall and rear wall.